Plug-in electric vehicles may be charged with a variety of different power sources and charging arrangements. For example, it is possible to charge some plug-in electric vehicles with an extension cord connected to a standard electrical outlet, such as a 110V or 220V outlet (so-called “mode 1” charging). Other vehicles may be charged using a specific charge coupling with internal protection features that connects to a standard electrical outlet, like a 110V or 220V outlet (“mode 2” charging). Some vehicles use a specific charge coupling that plugs into a certain type of electrical outlet, such as one that allows for various charging control features, and is connected to a dedicated electrical circuit (“mode 3” charging). And yet other vehicles may be charged via a specialized charge coupling that connects to an external high-voltage charger, such as one that is part of a charging station or kiosk and provides 200V-600V of DC power (“mode 4” charging). A variety of different charge couplings, outlets, arrangements, methods, etc. exist for charging plug-in electric vehicles, each with its own advantages and disadvantages.
One advantage of charging a plug-in electric vehicle with an external high-voltage charger (mode 4 charging) is the rapid rate of charging. This type of charging arrangement, which is also called “fast charging,” can significantly reduce charging times as it may provide between 10 kW-300 kW of charging power. However, if used frequently and without any constraints, fast charging from an external high-voltage power source can take a toll on the plug-in electric vehicle's battery and can reduce its useful battery life. The term “fast charging,” as used herein, includes any charging event or arrangement where an external power source charges a plug-in electric vehicle with a charge rate that exceeds the C-Rate of the vehicle's battery (i.e., the theoretical amount of current the battery can deliver when discharged in one hour to the point of 100% depth of discharge). For example, if the vehicle battery has a C-Rate of 45 Amp-hours, then any charging event exceeding 45 Amps could be considered a “fast charging” event.